Hi-Q Physics

ampere

SI unit of electric current. one ampere is a flow of one coulomb of charges per secong-6.25 x 10 to 18 elecrons (or protons) per second

ammeter

a device that messures current

acceleration due to gravity

acceleration of a freely falling object. its value near the earth's surface is about 9.8 meters per second each second.

de Broglie matter waves

all particles have wave properties; in de Broglie's equation, the product of momentum and wavelength equals Planck's constant

Britist thermal unit (BTU)

amount of heat required to change the temperature of 1 pound of water by 1 Fahrenheit degree

angle of incidence

angle between an incident ray and the normal to the surface it encounters.

angle of reflection

angle between the reflected ray and the normal to the surface of reflection.

angle of refraction

angle between the refracted ray and the normal to the surface at which it is reflected.

antiproton

antiparticles of a proton; a negatively charged proton.

circuit

any complete path along which electric charge can flow

antinode

any part of a standing wave with maximum displacement and maximum energy

complementary colors

any two colors of light that, when added, produce white light

buoyancy

apparent lost of weight of an object immersed or submerged in a liquid

centrifugal force

apparent outward force on a rotating or revolving body

blind spot

area of the retina where all nerves carrying visual information exit the eye and go the brain; this is a region of no vision

centripetal force

center-directed force that causes an object to follow a curved or circular path

boiling

change from liquid to gas occuring beneath the surface of the liquid; rapid vaporization; liquid loses energy, the gas gains it

condensation

change of phase of a gas intoa liquid

DDT

chemical pesticide called dichloro diphenyl tricholroethane

destructive interference

combination of waves so that crest parts of one wave overlap the trough parts of another, resulting in a wave of decreased amplitude

constructive interference

combination of waves so that two or more waves overlap to produce a resulting wave of increased amplitude

black hole

concentration of mass resulting from gravitational collapse, near which gravity is so intense that not even light can escape

abosorption spectrum

continous spectrum, like that generated by white light, intterupted by dark lines or bands that result from the abosorption of light of certain frequencies by a substance through which the light passes

astigmatism

defect of the eye caused when the cornea is curved more in one direction than in other.

circuit breaker

device in an electric circuit that breaks the circuit when the current gets high enough to risk causing a fire

barometer

device used to measure the pressure of the atmosphere

capacitor

device used to store charge in a circuit

aberration

distortion in an image produced by a lens or mirror, caused by limitions inherent to some degree in all optical systems

chromatic abberation

distortion of an image caused when light of different colors focuses at different points when passing through a lens

absorption lines

drak lines that appear in an absorption spectrum. the pattern of lines is unique for each element

alternating current

electric current that rapidly reverses in direction, the eletric chages vibrate about relatively fixed postions, usually at the rate of 60 hertz

beta particle

electron (or positron) emitted during the radioactive decay of certain nuclei

conduction electrons

electrons in a metal that move freely and carry electric charge

Avagadro's principle

equal volumes of all gases at the same temprature and pressure contain th same number of molecules, 6.02e23 in one mole

amplitude

for a wave or vibration, the maximum displacement on either side of the equilibrim (midpoint) position

air resistance

friction, or drag, that acts on something moving through air

aurora borealis

glowing of the atmosphere caused by ions from above the atmosphere that dip into the atmosphere; also called northern lights

Brownian motion

haphazard movement of tiny particles suspended in a gas or liquid resulting from bombardment by the fast-moving molecules of the gas or liquid

carrier wave

high-frequency radio wave modifed by a lower-frequency radio wave

Carnot efficiency

ideal maximum percentage of input energy that can be converted to work in a heat engine

correspondence principle

if a new theory is valid, it must account for the verified results of the old theory in the region where both theories apply

conduction

in heat, energy transfer from particle to particle within certain materials, or from one material to another when the two are in direct contact; in electricity, the flow of electric charge through a conductor

blue shift

increase in the measured frequency of light from an approaching source

aneroid barometer

instrument used to measure atmosheric pressure; based on the movement of the lid of a mental box, rather than on the movement of a liquid.

deuterium

isotope of hydrogen whose atom has a proton, a neutron, and an electron; the common isotope of hydrogen has only a proton and an electron; therefore, deuterium has more mass

converging lens

lens that is thicker in the middle than at the enges and refracts parallel rays of light passing through it to a focus

bioluminscence

light emitted from certain living things that have the ability to chemically excite molecules in their bodies; these excited molecules then give off visible light

coherent light

light of a single frequency with all photons exactly in phase and moving in the same direction

atomic bonding

linking together of atoms to form larger structures, such as molecules and solids

absolute zero

lowest possible temperature that any substance can have; the temperature at which the atoms of a substance have their minimum kinetic energy. the tempertaure of aboslute zero is -273.15 which is -459.7 and 0 kelvin

biomagnetism

magnetic material located in living organisms that may help them navigate, locate food, and affect other behaviors

antimatter

matter composed to atoms with negative nuclei and positive electrons.

convection

means of heat transfer by movement of the heated substance itself, such as by currents in a fluid

critical angle

minimum angle of incidence for which a light ray is totally reflected within a medium

critical mass

minimum mass of fissionable material in a nuclear reactor or nuclear bomb that will sustain a chain reaction

adhestion

molecular attraction between two surfaces making contact

bouyant force

net upward force exerted by a fluid on a submerged or immersed object

breeder reactor

nuclear fission reactor that not only produces power but produces more nuclear fuel than it consumes by converting a nonfissionable uranium isotope into a fissionable plutonium isotope

alpha particles

nucleus of a helium atom, which consists of two neutrons and two protons, ejected by certain radioactive nuclei

atomic number

number associatde with an atom, equal to the number of protons in the nucleus, or, equivalently, to the number of electrons in the electron cloud of a neutral atom

atomic mass number

number associated with an atom, equal to the number of nucleons in the nucleus

action force

one of the pair of forces described in Newton's third law

crest

part of a wave that is highest or the disturbance is greatest

armature

part of an electric motor or generator where an electromotive force is produced. usuallt the rotating part.

cyclotron

particle accelerator that imparts high energy to charged particles such as protons, deuterons, and helium ions

antiparticles

particles having the same mass as a normal particle, but a charge of the oppsite sign. the antiparticles of an electron is a positron.

center of mass

point at the center of an object's mass distribution

center of gravity

point at the center of an object's weight distribution

apogee

pointed in an elliptical orbit farthest from the focus around which orbiting takes place.

alchemist

practitioner of the early form of chemistry called alchemy, which was associated with magic. the goal of alchemywas to change base metals to gold and to discover a potion that could produce eternal youth

atmospheric pressure

pressure exerted against bodies immersed in the atmoshere resulting from the weight of air pressing down from above. at sea level, atmospheric pressure is about 101kPa

Bernoulli's Principle

pressure in a fluid decreases as the speed of the fluid increases

complementarity

principle enunciated by Niels Bohr stating that the wave and particle aspects of both matter and radiation are necessary, complementary parts of the whole

carbon dating

process of determining the time that has elapsed since death by measuring the radioactivity of the remaining carbon-14 isotopes

adiabatic process

process, often of fast expansion or compression, wherein no heat enters or leaves a system. as a result, a liquid or gas undergoing an expansion will cool, or undergoing a compression will warm

angular momentum

product of a body's rotational inertia and rotational velocity about a particlar axis. for an object that is small compared with the radial distance, it is the product of mass, speed, and radial distance of rotation.

acceleration

rate at which an object's velocity charges with time; the changes in velocity may be magnitude (speed), or direction, or both

Coulomb's Law

relationship among electrical force, charges, and distance: the electrical force between two charges varies directly as the product of the charges and inversely as the square of the distance between them

Archimede' particles

relationship between buoyancy and displaced fluid: An immersedobject is buoyed up by a force equal to the weight of the fluid it displaced.

capillarity

rise of a liquid in a fine, hollow tube or in a narrow space

beats

sequence of alternating reinforcement and cancellation of two sets of superimposed waves differing in frequency, heard as a throbbing sound

analog signal

signal based on a continuous variable, as opposed to a digital signal made up of discete quantities.

butterfly effect

situation in which a very small change in one place can amplify into a large change somewhere else

atom

smallest particle of an element that has all the element's chemical properties; consists of protons and neutrons in a nucleus surrounded by electrons

alloy

solid mixture composed of two or more metals or of metals and nonmetal

atomic mass unit

standard unit of atomic mass; it is based on the mass of the common carbon atom, which is arbitrarily given the value of exactly 12; an amu of one is one-twelfth the mass of this common carbon atom

alpha ray

stream of alpha particles (helium nuclei) ejected by certain radioactive nuclei

acoustics

study of the properties of sound, especially its transmisstion.

adiabatic

term applied to expansion or compression of a gas occuring without gain or loss of heat.

compression

the act of squeezing material and reducing its volume

Big Bang

the premordial explosion that is thought to have resulted in the creation of our expanding universe

Boyle's Law

the product of the pressure and volume is a constant for a given mass of confined gas regardless of changes in either pressure or volume individually, as long as temperature remains unchanged

additve primary colors

three colors of light-red, blue, and green- that when added in certain proportions will produce any color of the spectrum

bimetallic strip

two strips of different metals welded together or riveted together; used in thermostats

amplitude modulation

type of modulation in which the amplitude of the carried wave is varied above and below its normal value by an amount proportional to the amplitude of the impressed signal.

calorie (cal)

unit of heat; one calorie is the heat required to raise the temperature of one gram of water 1 Celsius degree

bel

unit of intensity of sound, named after Alexander Graham Bell; often measured in decibels

bow wave

v-shaped wave produce by an object moving on a liquid surface faster than the wave speed

chinook

warm, dry wind that blows down from the eastern side of the Rocky Mountains across the Great Plains

conservation of angular momentum

when no external torque acts on an object or a system of objects, no change of angular momentum takes place